From 41893389a6fb6d4d8b181cd90ca58d9d65326f76 Mon Sep 17 00:00:00 2001
From: Chris O'Hara <cohara87@gmail.com>
Date: Mon, 8 May 2023 17:06:08 +1000
Subject: [PATCH] syscall: implement wasip1 SetNonblock and IsNonblock
Allows for the NONBLOCK file descriptor flag to be set and queried
on wasip1.
syscall.SetNonblock uses the fd_fdstat_set_flags WASI system call
and unix.IsNonblock uses the fd_fdstat_get system call.
This is a prerequisite for non-blocking I/O support.
Change-Id: I2bf79fd57142b2ec53eed3977d9aac8c6337eb80
Reviewed-on: https://go-review.googlesource.com/c/go/+/493356
Auto-Submit: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
Run-TryBot: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
Reviewed-by: Julien Fabre <ju.pryz@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Achille Roussel <achille.roussel@gmail.com>
---
.../syscall/unix/nonblocking_wasip1.go | 18 +++++++++++++-
src/syscall/fs_wasip1.go | 24 +++++++++++++++++++
src/syscall/net_wasip1.go | 4 ----
src/syscall/syscall_wasip1.go | 14 +++++++++++
4 files changed, 55 insertions(+), 5 deletions(-)
diff --git a/src/internal/syscall/unix/nonblocking_wasip1.go b/src/internal/syscall/unix/nonblocking_wasip1.go
index 49a2a232bab..208db28c3ef 100644
--- a/src/internal/syscall/unix/nonblocking_wasip1.go
+++ b/src/internal/syscall/unix/nonblocking_wasip1.go
@@ -6,6 +6,22 @@
package unix
+import (
+ "syscall"
+ _ "unsafe" // for go:linkname
+)
+
func IsNonblock(fd int) (nonblocking bool, err error) {
- return false, nil
+ flags, e1 := fd_fdstat_get_flags(fd)
+ if e1 != nil {
+ return false, e1
+ }
+ return flags&syscall.FDFLAG_NONBLOCK != 0, nil
}
+
+// This helper is implemented in the syscall package. It means we don't have
+// to redefine the fd_fdstat_get host import or the fdstat struct it
+// populates.
+//
+//go:linkname fd_fdstat_get_flags syscall.fd_fdstat_get_flags
+func fd_fdstat_get_flags(fd int) (uint32, error)
diff --git a/src/syscall/fs_wasip1.go b/src/syscall/fs_wasip1.go
index 84c65c070f6..25cabf82343 100644
--- a/src/syscall/fs_wasip1.go
+++ b/src/syscall/fs_wasip1.go
@@ -255,6 +255,30 @@ func path_open(rootFD int32, dirflags lookupflags, path unsafe.Pointer, pathLen
//go:noescape
func random_get(buf unsafe.Pointer, bufLen size) Errno
+// https://github.com/WebAssembly/WASI/blob/a2b96e81c0586125cc4dc79a5be0b78d9a059925/legacy/preview1/docs.md#-fdstat-record
+// fdflags must be at offset 2, hence the uint16 type rather than the
+// fdflags (uint32) type.
+type fdstat struct {
+ filetype filetype
+ fdflags uint16
+ rightsBase rights
+ rightsInheriting rights
+}
+
+//go:wasmimport wasi_snapshot_preview1 fd_fdstat_get
+//go:noescape
+func fd_fdstat_get(fd int32, buf unsafe.Pointer) Errno
+
+//go:wasmimport wasi_snapshot_preview1 fd_fdstat_set_flags
+//go:noescape
+func fd_fdstat_set_flags(fd int32, flags fdflags) Errno
+
+func fd_fdstat_get_flags(fd int) (uint32, error) {
+ var stat fdstat
+ errno := fd_fdstat_get(int32(fd), unsafe.Pointer(&stat))
+ return uint32(stat.fdflags), errnoErr(errno)
+}
+
type preopentype = uint8
const (
diff --git a/src/syscall/net_wasip1.go b/src/syscall/net_wasip1.go
index d41e873bed2..896dd3e7708 100644
--- a/src/syscall/net_wasip1.go
+++ b/src/syscall/net_wasip1.go
@@ -122,7 +122,3 @@ func SetWriteDeadline(fd int, t int64) error {
func Shutdown(fd int, how int) error {
return ENOSYS
}
-
-func SetNonblock(fd int, nonblocking bool) error {
- return ENOSYS
-}
diff --git a/src/syscall/syscall_wasip1.go b/src/syscall/syscall_wasip1.go
index 73a461763ab..5d19c000ae6 100644
--- a/src/syscall/syscall_wasip1.go
+++ b/src/syscall/syscall_wasip1.go
@@ -464,3 +464,17 @@ const (
//go:wasmimport wasi_snapshot_preview1 clock_time_get
//go:noescape
func clock_time_get(id clockid, precision timestamp, time unsafe.Pointer) Errno
+
+func SetNonblock(fd int, nonblocking bool) error {
+ flags, err := fd_fdstat_get_flags(fd)
+ if err != nil {
+ return err
+ }
+ if nonblocking {
+ flags |= FDFLAG_NONBLOCK
+ } else {
+ flags &^= FDFLAG_NONBLOCK
+ }
+ errno := fd_fdstat_set_flags(int32(fd), flags)
+ return errnoErr(errno)
+}
--
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